Women, on average, earn less than their male peers. How much less depends on a number of factors.

The first rebuttal one hears when trying to discuss pay discrimination is, “But are we taking about equal work?” And the answer is yes, women do get paid less for doing the same work as their male peers. It’s why the Lilly Ledbetter Fair Pay Act exists. Ledbetter worked as an overnight supervisor at the Goodyear Tire and Rubber Company for nearly two decades. Just as she was about to retire, she received an anonymous note alerting her to the fact that she was making $3,727 per month, while men doing the same job — the same job — were being paid between $4,286 to $5,236 per month.

Ledbetter isn’t some anomaly. She is the face of the insidious operations of pay discrimination. It’s why there is now a law named after her. (A law that people like Rick Perry do not want to enforce.)

Here are some other examples of pay inequity within a single job, according to a breakdown of median weekly salaries from the Bureau of Labor Statistics:

A male education administrator makes, on average, $1,566 a week. His female colleague earns, on average, 67 percent of that salary.

A male high school teacher makes, on average, $1,050 a week. His female colleague earns, on average, 93 percent of that.

A male physician makes, on average, $2,099 a week. His female colleague earns, on average, 67 percent of that.

This trend continues across fields. For bus drivers, cooks, executives and baby sitters. (Yes, even baby sitters.) In fact, among the Bureau’s nearly 600 listed occupations, women earn less than men in all but seven of them.

The pay gap persists even when you factor in hours worked, family leave and other variables.

The second thing a pay gap skeptic will probably tell you is, “Some women work less hours and take time off to raise families or care for ailing relatives. That’s why they make less money than men.” And the answer is yes, women do shoulder a disproportionate amount of the labor of raising families or caring for sick relatives. But rather than debunking the pay gap, the unequal distribution of this kind of labor among men and women is actually driving it.

A 2003 report from the Government Accountability Office reveals that the pay gap persists between men and women — even after one takes into account part-time work and women working fewer hours or taking time off to raise children or care for family members. After doing a quantitative analysis of a nationally representative longitudinal data set, the GAO found that while many factors influence wage disparities, when you remove all of these differences, women still earn around 80 percent of men’s wages. As the authors of the report note, “Even after accounting for key factors that affect earnings, our model could not explain all of the difference in earnings between men and women.”

Other studies have found a narrower gap in certain industries, but a gap nonetheless. The American Association of University Women found that among recent college graduates with the same credentials, a 6 percent pay gap remained, and that gap expanded to 12 percent over time. Even in the “best cities” for pay equity, women are still earning 90 percent of their male colleagues’ salaries.

Decades of research shows a gender gap in pay even after factors like the kind of work performed and qualifications (education and experience) are taken into account. These studies consistently conclude that discrimination is the best explanation of the remaining difference in pay. Economists generally attribute about 40 percent of the pay gap to discrimination — making about 60 percent explained by differences between workers or their jobs.

And those “explained” differences don’t account for the fact that the “choices” girls and women make about education, career and family are shaped by deeply gendered cultural norms.

Rather than take for granted that women work fewer hours because they genuinely prefer it, policymakers have started to examine the question of why women are disproportionately doing the kind of labor — primary parenting, for example — that requires time off work. On the matter of women’s “choices,” White House economic adviser Betsey Stevenson recently told MSNBC, “Some of women’s choices come because they experience sexism. Some of women’s choices come because they are disproportionately balancing the needs of work and family. Which of these choices should we consider legitimate choices, and which of them should we consider things that we have a societal obligation to try to mitigate?”

The pay gap is worse for women of color and LBTQ women.

It is, at this point, safe to say that the pay gap is in part driven by sexism in its many manifestations, both institutional and cultural. But pay discrimination is also a product of entrenched racism and homophobia.

African-American women who work full-time year round earn 64 cents on the dollar; Latina women earn 54 cents for every dollar earned by a white, non-Hispanic colleague. As data from the National Women’s Law Center points out, these gaps “translated into a loss of $18,650 for African-American women and $24,111 for Hispanic women in 2012.” Asian-American women’s salaries show the smallest pay gap — but they are still earning, on average, 87 cents on the dollar.

Two out of every three minimum wage workers is a woman, and many of those women are also mothers or the primary caregivers in their households. This is why policymakers include raising the minimum wage in their recommendations for closing the gender earnings gap.

As I’ve pointed out before, raising the federal minimum wage from $7.25 to a meager $10.10 an hour would boost earnings for 28 million workers, and would help lift millions of women out of poverty. More than 25 percent of low-wage and low-income workers are single mothers, but at the current minimum wage, a woman who works full-time can expect to make an average of $14,500 each year. That’s $4,000 less than the poverty level for a mother of two children.

According to a recent White House report, “Estimates from the President’s Council of Economic Advisers suggest that increasing the minimum wage to $10.10 an hour and indexing it to inflation could close about 5 percent of the gender wage gap.”

As the report also notes, women breadwinners in low-income families contribute a bigger share of their family’s financial resources than women in higher-income households. A small increase to the minimum wage could translate to a major boost for families fighting to stay afloat.

As Dave Jamieson at the Huffington Post notes, women “account for the majority of workers in the 10 largest jobs that pay below $10.10 per hour, including housekeepers, cashiers and childcare workers.” And according to the National Women’s Law Center, the gender gap is worse in states that haven’t raised their minimum wage above the meager federal level of $7.25 an hour.